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Technical Service Bulletin Transaction No.: 2080517/1
27 12V Starter battery discharged or malfunctioning Release date: Dec 19, 2025
Condition

Model(s) Year(s) VIN Range Vehicle Specific Equipment
All Audi vehicles | 2015 - 2026 All Not applicable

12v Battery discharged, faulty:

1.

2.
3.

The analysis of the damaged parts sent in to be checked shows a high proportion of batteries which are OK
and were replaced without good reason.

Battery reached its wear limit prematurely, e.g. due to battery maintenance program not being carried out.

Technical causes.

Technical Background

Battery discharged/faulty due to:

Customer influence (ignition on, light on, extremely short distances driven, long stationary periods, ....).
No-load currents.

Bus sleep inhibitors, bus alarms.

Battery charging performed insufficiently or not at all as part of stock vehicle maintenance.

No external power supply on showroom vehicles. Requirement: charger permanently connected, at least 30 A
charging current.

Battery check performed incorrectly.

Production Solution

Evaluation of historical battery data as part of fault finding.
Various measures to fix no-load current and bus issues (see respective TSBs).
Requirements for performing stock vehicle maintenance.

Requirements for handling showroom vehicles.

Service

Proceed as follows:

Battery test with Guided Fault Finding:

Check 12V battery using test plan "A — Battery (12V), test" in Guided Fault Finding
Battery test as part of pre-delivery inspection (only for new vehicle before delivery)
Battery test for used batteries (all vehicles after first delivery)
Battery test with tester or measuring tools if Guided Fault Finding cannot be performed, or the battery is
evaluated as being OK and the customer has complained (energy-critical state):

If it has not been possible to detect a cause on the vehicle itself up to now, test the battery with VAS 6161
(after fully charging the battery and starting the engine 5 times).

If VAS 5097A is available, use it instead.

(Recommendation: Please leave the battery to charge for at least 12 hours or until it has reached 80% SOC.
After this, leave the battery standing for two hours and then test it using battery tester VAS 5097A , and then
leave it standing again for at least 30 minutes. Then carry out another load test. Both results should be “good”
or better.)

Read out completely decrypted history data and perform an analysis (read data for TSC, do not read the raw
data)

Based on the data, determine the cause as to why the battery discharges (excessive no-load current/bus
wake-up/bus sleep inhibitor) or why the 12V battery does not charge (alternator defective, belt-driven starter-
alternator defective; DC/DC converter defective; wiring issue etc.).

Use history data 6 to check the trip energy balance (charging and discharging the battery while driving) (see
attachment...).

Use history data 7 to check the stationary energy balance (discharging the battery while stationary) (see
attachment...).

Discharge / no-load current too high:

Check whether any retrofitted equipment is available (towing bracket, GPS tracker, dash cam, marten
repellent system, additional non-standard lighting, etc.).

Use the test plan offered in Guided Fault Finding/ODIS (if event memory entry "No-load current too high" is
logged in diagnostic address 0019, observe time frame in relation to customer complaint).

Alternatively, select Own test plan -> No-load current measurement

Check for bus wake-up or bus sleep inhibitor (see examples in attachments)

12V battery not charging:

Vehicles with conventional alternators:
Alternator not working (check alternator test plan)
Vehicles with 12V MHEV system:

Belt-driven starter-alternator not working (for test plan, see event memory entries in engine/motor control unit
diagnostic address 0001)

Vehicles with 48V MHEV system:

Belt-driven starter-alternator not working (for test plan see event memory entries in:
Diagnostic address 0001 (engine/motor control unit)
Diagnostic address 00CC (belt-driven starter-alternator)
Diagnostic address 0019 (gateway)

Diagnostic address 0021 (48V battery)

Diagnostic address 00C4 (voltage converter)
Diagnostic address 0051 (powertrain generator)
Vehicles with PHEV system:

Event memory entry in diagnostic address 0051
Vehicles with BEV system:

Event memory entry in diagnostic address 00C6

Check whether there are event memory entries in the diagnostic addresses. If there are event memory entries,
work through the provided test plans for the event memory entries using Guided Fault Finding.

Erase the event memory and re-evaluate the system with meaningful history data (read out data for TSC; not
the raw data).
Possible faults when charging/checking battery:

Battery not charged
despite the charger
being connected

Clamps do not make optimal contact

Check good contact is made; check clamps for
dirt/oxidation

Charger incorrectly adjusted

Perform adjustment according to instruction
manual

Charger damaged

Measure charging current with an ammeter

Test result from VAS
5097A does not
correspond to
battery’s actual
condition

Adjustment of battery capacity on
tester incorrect

Adjust current on tester depending on battery
capacity

Copper bridge in clamps cracked
(Figure 1)

Replace cable with clamps

Poor contact, oxidation on contact
surface (Figure 2)

Clean or replace clamps

Copper core cracked (Figure 3)

Replace cable with clamps

Figure 2. Oxidation on contact surface.

Figure 3. Copper core cracked.

Warranty

Note: Batteries which are sent in without a battery check via GFF and historical battery data will be charged
back.

Please note:

* Batteries identified as faulty according to the tests described above:
Service number/damage code/manufacturer: 2706/0040/...

* Ifa specific cause for the discharged batteries is found, encrypt the part/control unit causing the damage.

* — If the analysis shows that customer behavior has led to the battery being discharged, for example because the
light or the ignition was left on, invoicing under warranty is not permitted.

Faulty batteries replaced because of incorrect handling, such as failure to perform stock vehicle
maintenance or leave the charger permanently connected to showroom vehicles (or similar), must not be
invoiced under warranty.

Claim Type: * If the vehicle is outside of any warranty, this Technical Service Bulletin is
informational only.
Service Number: 2706
Damage Code: 0040
Labor Operations: GFF / Guided Functions 0150 0010 See SRT with
associated operations
GFF / Guided Functions 0150 0060 Time stated on the
diagnostic protocol
Claim Comment: As per TSB 2080517/1

All warranty claims submitted for payment must be in accordance with the Audi Warranty Policies and Procedures
Manual. Claims are subject to review or audit by Audi Warranty.
Please note the information on predecessors and items that are included and excluded in the repair operations, as
well as any associated tasks.

Please use the operations available in ELSA to bill for the required maintenance work.

Additional Information

All parts and service references provided in this TSB (2080517) are subject to change and/or removal.

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